Thomas r



(No Model.)

T. R. ALMOND.

FLEXIBLE TUBE.

No. 434,748. Patented Aug. 19, 1890.

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UNITED STATES- PATENT OFFICE.

THOMAS R. ALMOND, OF NEW YORK, N. Y.

FLEXIBLE TUBE.

srncrrron'rron forming part of Letters Patent No.'4s4,74s, dated; August19,1890.

Application filed April 24, 1890. Serial No. 349, 3- (No model) To allwhom it may concern:

Be it known that I, THOMAS R. ALMOND, a resident of the city, county,and State of New York, have invented an Improved Flexible Tube, of whichthe following is a specification.

This invention relates to improvements on the flexible tube for whichLetters Patent of the United States No. 4243M: were granted to me March25, 1890.

The invention consists, mainly,in combininga coil of triangularcross-section with an inner coil, between the convolutions of which thetriangular windings of the outer coil are forced, all ashereinafter morefully described.

The invention also consists in concaving the faces of said triangularcoil; also in combining therewith peculiar shapes of the innercoil, ashereinafter specified.

In the drawings, Figure 1 represents a longitudinal central section of aflexible tube made according to this invention, showing it on a mandrel;Fig. 2 is a similar View on a a larger scale of said tube partly in faceview. Figs. 3, 4, and 5 are sectional diagrams showing different formsof parts.

In my Letters Patent No. 424,0il, I show a flexible tube composed mainlyof two coils of wire, one of which is placed around a man- (1 rel, theother being forced into the interstices between the convolutions of thefirst coil, so as finally to enter between the convolutions of the firstcoil and reach contact with the mandrel. This arrangement is departedfrom in the present instance in thatI use an outer coil A of triangularcross-section,which outer coil I force between the convolutions of theinner coil D while the same bears on the mandrel B, so that thus thetapering or wedgelike edges of the outer coil A will serve to at alltimes keep the convolutions of the inner coil D under tension, seekingto spread them apart, where otherwise they would tend to approach oneanother. By imparting to the outer coil A this triangular formI obtainthe additional advantage of securing a larger contact-face than isobtained by the cylindrical wire shown in my former patent and ofinsuring a more perfect closure while the flexible pipe is bent.

The triangle of the outer coil A may be equilateral and straightsided,as in Fig. 4.; but I much prefer to make the contact-faces a a, whichbutt against the coil D, of concave form, the curvature being on acircle of which the center lies in the axis of the mandrel B. Thiscurved or concaved triangle in contact with the inner coil D is shown inFig. 3 and has the advantage of giving a still greatercontact-face andof producinga tighter joint when the tube is bent; but Fig. 5 shows astillbetter form in that the inner coil D has contact-faces b on thesame curve as the contact-faces a of the concave triangles A.

One way of making this improved tube is to first place around a mandrelBthe coil D and then to force between the convolutions of that coil thetriangular coil A, so that the wedge-like convolutions of this coil Awill enter between the convolutions of the coil D, tending to spreadthem apart, and insuring therefore a tight joint, which will bemaintained tight even when the tube is bent to a reasonable degree. 7 Inusing the tube the mandrel is of course removed.

lVhat I claim, and desire to secure by Letters Patent, is- A 1. Theflexible tube composed of an inner coil combined with the outer coil A,of triangular cross-section. whose convolutions are in* terposed betweenthe convolutions of the inner coil, substantially as herein shown anddescribed.

2. The flexible tube composed of the inner coil D, combined with theouter coil A, of trlangular cross-section, having concave faces a, thecoil D having curved faces I) corresponding'to the concave faces a ofthe coil A, the convolutions of the coil A being interposed between theconvolutions of the coil D, so that the concave faces a a are in contactwith the convex-faces Z2, substantially as herein shown and described.

THOMAS E. ALMOND.

Witnesses: I

HARRY M. TURK, LIVINGSTON EMERY.

